1. Field of the Invention
The present invention relates generally to a Code Division Multiple Access (CDMA) communication system. More particularly, the present invention relates to a method for efficiently managing additional service information of a subscriber between the mobile switching center (MSC) and the home location register (HLR).
2. Description of the Related Art
In order to initiate various service features provided in a mobile communication system, a subscriber usually presses one of the predetermined keys (e.g., *+digits+SEND key) to activate/deactivate additional service functions (i.e., call forwarding, voice mailing service, three way callng, etc.). In response to such commands, an Access Switching Processor (ASP) 111, which is provided in the originating MSC 110 to perform the message transmission to process the mobile call and manage the state management of the subscriber, transmits a feature request (FEATREQ) 210 message consisting of MIN, ESN, digits, MSCID, and other parameters relating to the subscriber, to the HLR 120. As shown in FIG. 2, the HLR 120 searches its own database based on the key input pressed by the subscriber to determine whether the requesting subscriber is registered for the additional service function. If the requesting subscriber is not registered for the additional service, the HLR 120 transmits a FEATREQ RESPONSE message 220 notifying the ASP 111 accordingly using the Announcement_List parameter of the FEATREQ RESPONSE message 220.
On the other hand, if the subscriber is registered to receive the additional service function, the HLR 120 updates additional service information of the subscriber in the database and transmits a FEATREQ RESPONSE message 220, which includes the parameters of Announcement_List and FeatureResult to the ASP 111. Then, the HLR 120 transmits a qualification directive (QUALDIR) message 230, which contains the parameters of MIN, ESN, CFI (Calling Feature Request), and etc., to a Visitor Location Register (VLR) 112 of the originating MSC to transfer the updated information of the subscriber in the VLR 112. Upon receipt of the QUALDIR message 230, the VLR 112 updates the subscriber information received from the HLR 120 and transmits a qualification directive (qualdir) response message to notify the completion of an update to the HLR 120.
As stated above in the conventional method, the HLR and the MSC together manage information necessary to activate/deactivate the additional service function during a maintenance & repair (MAP) procedure between the MSC and the HLR.
The HLR transmits a QUALDIR message to the MSC either when the OMP of the HLR changes the additional service information of the subscriber or when the MSC transmits the FEATREQ message to the HLR in response to the user's request. More frequent changes in requesting for different services through the HLR are usually initiated by the subscribers then the operator.
Therefore, the transmission of FEATREQ RESPONSE message 220 in response to the FEATREQ message 210 for activation/deactivation of the additional service, and the QUALDIR message for updating database of the VLR of the originating MSC by the HLR are inefficiently performed in the current procedure. As the maintenance & repair procedure is complicated by multiple execution steps, errors are more likely to happen. Consequently, in the event that errors occur between the HLR and the MSC, reliable subscriber information can not be provided between the systems. Therefore, the present invention proposes a more efficient way to simplify the maintenance & repair procedure.